Detection and temporal coherence of p-modes below 1.4 mHz
Abstract
Data collected recently by the helioseismic experiments aboard the SOHO spacecraft have allowed the detection of low degree p-modes with increasingly lower order n. In particular, the GOLF experiment is currently able to unambiguously identify low degree modes with frequencies as low as 1.3 mHz. The detection of p-modes with very low frequency ({i.e.}, low n), is difficult due to the low signal-to-noise ratio in this spectral region and its contamination by solar signals that are not of acoustic origin. To address this problem without using any theoretical a priory, we propose a methodology that relies only on the inversion of observed values to define a spectral window for the expected locations of these low frequency modes. The application of this method to 2920-day-long GOLF observations is presented and its results discussed.
- Publication:
-
Astronomische Nachrichten
- Pub Date:
- June 2008
- DOI:
- 10.1002/asna.200710990
- Bibcode:
- 2008AN....329..470E
- Keywords:
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- methods: data analysis;
- Sun: helioseismology;
- Sun: interior